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Author: Stacy Nicole Trackenberg Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
Biogenic coastal habitats such as salt marshes, seagrasses, and oyster reefs, support diverse faunal communities and can serve as nursery areas by enhancing the abundance, growth, and survival of juvenile fish and crustaceans. The structure and complexity of these biogenic habitats can strongly influence the composition of marine faunal communities and contribute to their roles as nursery areas. It is imperative to understand how nursery areas are defined in the ecological literature as these definitions are applied to nursery area management across the United States. Further, the relative importance of how habitat structural attributes, which are influenced by abiotic and biotic factors, shape faunal communities within these nursery areas is critical to understand these important coastal ecosystems. My dissertation focuses on (1) how nursery frameworks in the ecological literature have evolved and how these frameworks are applied to state management of nursery areas; (2) how abiotic and biotic factors influence the restoration success and complexity of seagrass meadows; and (3) how, in turn, this habitat complexity influences faunal community composition and structure. For my first chapter, I found six overarching frameworks to define and delineate nursery areas in the ecological literature: measures of juvenile abundance and vital rates, habitat characteristics, seascape connectivity, populations fitness and contribution to adult biomass, and persistence. Of the 23 coastal states, only seven explicitly protect nursery areas and of these seven states, the aforementioned frameworks are not equally applied. Gathering and analyzing data necessary to integrate higher-order metrics (e.g., connectivity and biomass contribution) to designate nurseries will require significant research investment and greater collaboration between ecologists and fisheries scientists. My second chapter combines two years of observational seagrass and faunal surveys with a habitat preference experiment to investigate to which degree multiple seagrass complexity metrics influence the composition and abundance of faunal communities in North Carolina seagrass beds. Trawl surveys revealed that taller canopied seagrass beds support higher faunal abundances and species richness than shorter canopied beds, however this was not true across all species. There were species-specific relationships between complexity metrics and abundances, with these relationships shifting between the two years of our study, potentially due to the range of sampling months each year. Pinfish (Lagodon rhomboides), the most common fish found in North Carolina seagrass meadows demonstrated a preference for deep seagrass beds, but only preferred taller canopies when these areas also offered increased blade surface area. In Chapter 3, I conducted field surveys of natural seagrass beds to understand the spatio-temporal distribution and morphology of seagrasses in North Carolina coastal sounds and used these observations to inform a field transplantation experiment of the subtropical seagrass species, Halodule wrightii. Seagrass morphology differed across sampling months but only canopy height differed across depth. Depth was also influential in transplantation success with higher survival of intertidal seagrass transplants compared to subtidal. Considerations of both structural complexity and physical setting of the habitat are therefore imperative for a comprehensive approach in understanding how habitats as well as their faunal communities are responding to future changes across ecosystem settings.
Author: Stacy Nicole Trackenberg Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
Biogenic coastal habitats such as salt marshes, seagrasses, and oyster reefs, support diverse faunal communities and can serve as nursery areas by enhancing the abundance, growth, and survival of juvenile fish and crustaceans. The structure and complexity of these biogenic habitats can strongly influence the composition of marine faunal communities and contribute to their roles as nursery areas. It is imperative to understand how nursery areas are defined in the ecological literature as these definitions are applied to nursery area management across the United States. Further, the relative importance of how habitat structural attributes, which are influenced by abiotic and biotic factors, shape faunal communities within these nursery areas is critical to understand these important coastal ecosystems. My dissertation focuses on (1) how nursery frameworks in the ecological literature have evolved and how these frameworks are applied to state management of nursery areas; (2) how abiotic and biotic factors influence the restoration success and complexity of seagrass meadows; and (3) how, in turn, this habitat complexity influences faunal community composition and structure. For my first chapter, I found six overarching frameworks to define and delineate nursery areas in the ecological literature: measures of juvenile abundance and vital rates, habitat characteristics, seascape connectivity, populations fitness and contribution to adult biomass, and persistence. Of the 23 coastal states, only seven explicitly protect nursery areas and of these seven states, the aforementioned frameworks are not equally applied. Gathering and analyzing data necessary to integrate higher-order metrics (e.g., connectivity and biomass contribution) to designate nurseries will require significant research investment and greater collaboration between ecologists and fisheries scientists. My second chapter combines two years of observational seagrass and faunal surveys with a habitat preference experiment to investigate to which degree multiple seagrass complexity metrics influence the composition and abundance of faunal communities in North Carolina seagrass beds. Trawl surveys revealed that taller canopied seagrass beds support higher faunal abundances and species richness than shorter canopied beds, however this was not true across all species. There were species-specific relationships between complexity metrics and abundances, with these relationships shifting between the two years of our study, potentially due to the range of sampling months each year. Pinfish (Lagodon rhomboides), the most common fish found in North Carolina seagrass meadows demonstrated a preference for deep seagrass beds, but only preferred taller canopies when these areas also offered increased blade surface area. In Chapter 3, I conducted field surveys of natural seagrass beds to understand the spatio-temporal distribution and morphology of seagrasses in North Carolina coastal sounds and used these observations to inform a field transplantation experiment of the subtropical seagrass species, Halodule wrightii. Seagrass morphology differed across sampling months but only canopy height differed across depth. Depth was also influential in transplantation success with higher survival of intertidal seagrass transplants compared to subtidal. Considerations of both structural complexity and physical setting of the habitat are therefore imperative for a comprehensive approach in understanding how habitats as well as their faunal communities are responding to future changes across ecosystem settings.
Author: Anthony W. D. Larkum Publisher: Springer ISBN: 331971354X Category : Science Languages : en Pages : 791
Book Description
This book takes the place of “Biology of Seagrasses: A Treatise on the Biology of Seagrasses with Special Reference to the Australian Region”, co-edited by A.W.D. Larkum, A.J. MaCComb and S.A. Shepherd and published by Elsevier in 1989. The first book has been influential, but it is now 25 years since it was published and seagrass studies have progressed and developed considerably since then. The design of the current book follows in the steps of the first book. There are chapters on taxonomy, floral biology, biogeography and regional studies. The regional studies emphasize the importance of Australia having over half of the world’s 62 species, including some ten species published for Australia since the previous book. There are a number of chapters on ecology and biogeography; fish biology and fisheries and dugong biology are prominent chapters. Physiological aspects again play an important part, including new knowledge on the role of hydrogen sulphide in sediments and on photosynthetic processes. Climate change, pollution and environmental degradation this time gain an even more important part of the book. Decline of seagrasses around Australia are also discussed in detail in several chapters. Since the first book was published two new areas have received special attention: blue carbon and genomic studies. Seagrasses are now known to be a very important player in the formation of blue carbon, i.e. carbon that has a long turnover time in soils and sediments. Alongside salt marshes and mangroves, seagrasses are now recognized as playing a very important role in the formation of blue carbon. And because Australia has such an abundance and variety of seagrasses, their role in blue carbon production and turnover is of great importance. The first whole genomes of seagrasses are now available and Australia has played an important role here. It appears that seagrasses have several different suites of genes as compared with other (land) plants and even in comparison with freshwater hydrophytes. This difference is leading to important molecular biological studies where the new knowledge will be important to the understanding and conservation of seagrass ecosystems in Australia. Thus by reason of its natural abundance of diverse seagrasses and a sophisticated seagrass research community in Australia it is possible to produce a book which will be attractive to marine biologists, coastal scientists and conservationists from many countries around the world.
Author: Tracy Fisher Weatherall Publisher: ISBN: Category : Languages : en Pages :
Book Description
Satellite tracking data of juvenile and subadult green turtles captured and released by Texas A & M University at Galveston's Sea Turtle and Fisheries Ecology Research Lab (STFERL) from the lower Laguna Madre indicate green sea turtles (Chelonia mydas) exhibit high fidelity to seagrass communities where they can be found year-round. Population growth is prerequisite to eventual down listing of this endangered species to a threatened status and its subsequent recovery. The role Texas' green turtle population will play in this recovery will depend, in part, on the ability of seagrass communities in the lower Laguna Madre to sustain continued growth of this population. Seagrass community structure was characterized during 7-8 March 2009 to determine if foraging grounds in the lower Laguna Madre can sustain green turtle population growth. Differences in seagrass community structure influencing foraging potential between high fidelity sites (Region 1) were compared to adjacent areas in which green turtles have not been captured and tracked by the STFERL (Region 2). Seagrass samples were taken from six seagrass communities to characterize seagrass and invertebrate community parameters. In addition, three standardized and randomized bag seine collections of nekton, invertebrates and plant debris were conducted within the six seagrass communities. Family richness and abundance of fishes and invertebrate fauna were assessed from the standardized bag seine collections. Seagrass species including Thalassia testudinum (turtle grass), Syringodium filiforme (manatee grass), and Halodule wrightii (shoal grass) were found in Region 1 whereas T. testudinum and H. wrightii were found in Region 2. Total seagrass biomass from Region 1 was significantly greater than that from Region 2 implying a healthier seagrass community. Seagrass beds in Region 2 were highly patchy and sparse. Family richness and faunal density collected with the bag seine in Region 1 were significantly higher than those in Region 2 suggesting seagrass habitat complexity was higher in Region 1. These data suggest a trend toward increased seagrass habitat quality and community complexity in Region 1 which, in turn, may contribute to a healthier seagrass environment that serves as an optimal foraging area for green turtles in the lower Laguna Madre.
Author: Christian Hayes Publisher: ISBN: Category : Blue crab Languages : en Pages : 502
Book Description
Seagrass structural complexity is a primary driver of nekton recruitment and faunal community structure. Few studies, however, have quantified the role of seagrass complexity on habitat use and trophic structures over large spatial scales. A large-scale simultaneous survey was conducted to assess relationships of multiple seagrass morphological complexity metrics to nekton habitat use, trophic dynamics, and blue crab (Callinectes sapidus) growth and mortality across the Northern Gulf of Mexico. Seagrass morphological and nekton community characteristics depended on site and season, and regional variation in seagrass morphology was an important driver of juvenile nekton abundance, species richness, beta diversity, assemblage structure, and functional diversity across the Northern GOM. Results from a stable isotope survey indicate that food web structures across turtle grass (Thalassia testudinum)-dominated ecosystems are similar, although there was a clear trend of more depleted carbon isotopes in primary producers, fish, shrimp, and crabs at sites in the Eastern GOM and more enriched isotopes at sites in the Western GOM, which may be associated with site-specific differences in environmental conditions, such as freshwater inflow and nutrient inputs. Blue crab growth and mortality experiments revealed that growth and mortality rates varied across the six sites, but overall mortality rate declined with increasing seagrass leaf area index and crab size. Blue crab growth rates, however, had no measurable relationship with seagrass complexity metrics. Results from this work indicate that habitat complexity metrics such as shoot density, canopy height, and leaf area index are important factors that define the nursery functions of seagrass habitats and should be incorporated into monitoring programs, conservation initiatives, and fishery models. This study also demonstrates the utility of conducting large-scale comparative studies to reveal regional differences and similarities in trophic structures. Finally, this study highlights the need for additional regional and species-specific studies of environmental drivers of nekton community production throughout the GOM, and our results suggest that models of nekton production in seagrass habitats should be created at regional, as well as local, scales to identify broad patterns but also to account for site-specific differences in nekton responses to environmental and habitat characteristics.
Author: Victor S Kennedy Publisher: Elsevier ISBN: 1483277496 Category : Science Languages : en Pages : 556
Book Description
Estuarine Perspectives presents most of the invited papers presented at the Fifth Biennial International Research Conference on Estuarine Research. The book includes information on one tropical and two Arctic estuaries; contemporary techniques as applied to estuarine research; and some hypotheses of estuarine ecology. The text also describes value and management of wetlands as well as the chemical cycles and fluxes. The primary production and photosynthesis; the physical and biological factors of estuarine sediment; and the ecosystem dynamics are also encompassed.
Author: Publisher: ISBN: Category : Electronic books Languages : en Pages : 39
Book Description
A central theory of community ecology is that increased biodiversity results in greater ecosystem function and stability. Many experiments have examined biodiversity-ecosystem function (BEF) relationships at the primary producer level, yet BEF relationships are equally pertinent at higher trophic levels. In seagrass ecosystems, mesograzers (small invertebrate herbivores) promote seagrass persistence by consuming competitively superior epiphytic algae that foul seagrass blades. Experiments in seagrass habitat suggest that mesograzer diversity is a primary driver of top-down control of epiphytic algae, but also that the relationship is temporally and spatially variable. The primary hypothesis of my study is that much of this variability may be due to differences in seagrass habitat structure through time and space. I worked in eelgrass (Zostera marina) habitat in San Diego Bay, California, USA, to test whether variability in eelgrass structural complexity (shoot density) affects relationships between mesograzer biodiversity and ecosystem function (grazing impact and secondary production). I also examined the functional roles of numerically dominant eelgrass epifauna, using a laboratory experiment and stable isotope analysis. Contrary to BEF theory, increased grazer diversity in laboratory mesocosms resulted in decreased grazing impact and facilitation of algal growth. Though some species combinations resulted in increased algal grazing, antagonistic relationships among the most influential grazing taxa resulted in reduced ecosystem function. Structural complexity promoted mesograzer top-down control of epiphytes, increased mesograzer secondary production, and altered epifaunal community composition. Effects of biodiversity and structural complexity on grazing corresponded to variability in diet and feeding behavior among dominant epifaunal taxa. My results demonstrate the importance of examining species-specific interactions when considering links between community structure and ecosystem function, and that environmental context, such as habitat structure, may have large effects on BEF relationships.
Author: Frederick T. Short Publisher: Univ of California Press ISBN: 9780520240476 Category : Nature Languages : en Pages : 336
Book Description
Seagrasses are a vital and widespread but often overlooked coastal marine habitat. This volume provides a global survey of their distribution and conservation status.
Author: Publisher: ISBN: Category : Electronic books Languages : en Pages : 52
Book Description
Seagrasses form important coastal habitats that promote the foraging and survival of mesopredators. Variation in seagrass habitat structure at local and seascape scales mediates foraging success and survival, but the interactive effects of structure at these scales rarely is quantified when evaluating nursery habitat function. For my thesis, I tested how the interactions of multiscale habitat structural variation on juvenile fish body size mediates the value of seagrass habitat through survival and foraging success. In Chapter 1, I tested the hypothesis that in eelgrass (Zostera marina) optimal structural complexity (SC) for juvenile giant kelpfish (Heterostichus rostratus) changes through ontogeny. I found that habitat selection differed with kelpfish size: small and large fish selected high and low SC respectively. Smaller kelpfish experienced lower predation risk and higher foraging in high SC, suggesting high SC is selected by these fish because it minimizes risk and maximizes growth potential. Larger kelpfish experienced lower predation risk and higher foraging in high and low SC respectively, suggesting they select low SC to maximize foraging efficiency. My study highlights that trade-offs between predation risk and foraging can occur within a single habitat type, that studies should consider how habitat value changes through ontogeny, and that seagrass nursery habitat value may be maximal when within-patch variability in SC is high. In Chapter 2, I used a spatially explicit individual-based model to examine how seagrass fragmentation influences foraging and survival of a mesopredator, and how these relationships are influenced by SC, body size, and mesopredator and prey densities. I found that mesopredator survival and foraging dropped beyond threshold levels of habitat area (60 and 30% respectively) and depended on level of SC in the seascape. The relationship between habitat area and foraging did not depend on SC or body size, but did depend on organismal densities: when mesopredators and prey densities increased with decreasing habitat area, foraging was highest in highly fragmented seascapes. My results suggest that small- and large-scale habitat structure jointly dictate the value of a nursery habitat, and the effects of survival and foraging should consider interactions with habitat structure at multiple scales.
Author: S.S. Bell Publisher: Springer Science & Business Media ISBN: 9401130760 Category : Science Languages : en Pages : 451
Book Description
We conceived the idea for this book after teaching a graduate seminar on 'Habitat Complexity' at The University of South Florida. Discussions during the seminar led us to conclude that similar goals were to be found in studies of the topic that spanned the breadth of ecological research. Yet, the exact meaning of 'habitat structure', and the way in which it was measured, seemed to differ widely among subdisciplines. Our own research, which involves several sorts of ecology, convinced us that the differences among subdisciplines were indeed real ones, and that they did inhibit communica tion. We decided that interchange of ideas among researchers working in marine ecology, plant-animal interactions, physiological ecology, and other more-or-less independent fields would be worthwhile, in that it might lead to useful generalizations about 'habitat structure'. To foster this interchange of ideas. we organized a symposium to attract researchers working with a wide variety of organisms living in many habitats, but united in their interest in the topic of 'habitat structure'. The symposium was held at The University of South Florida's Chinsegut Hill Conference Center, in May. 1988. We asked participants to think about 'habitat structure' in new ways; to synthesize important, but fragmented, information; and. perhaps. to consider ways of translating ideas across systems. The chapters contained in this book reflect the participants' attempts to do so. The book is divided into four parts, by major themes that we have found useful categorizations.
Author: Stacy Nicole Trackenberg
Author: Stacy Nicole Trackenberg
Author: Anthony W. D. Larkum
Author: Tracy Fisher Weatherall
Author: Christian Hayes
Author: Victor S Kennedy
Author: 
Author: Frederick T. Short
Author: 
Author: Carly RoseAnn Steeves
Author: S.S. Bell